Engine cylinders for passenger vehicles may have one or more electrically actuated intake and/or exhaust valves. These electrically actuated valves can operate independently of a crankshaft and/or piston position, for example. Various modes of operating these valves may be provided for improving engine control and/or emission reduction.
One approach that uses adjustable valve operation to provide faster engine starting adjusts injection timing of direct injection fuel injection. For example, direct starting may be provided using such operation, where the cylinder spark is initiated to start engine rotation and thus remove the starter. Further, in another example, such operation can be used to reduce the size a starter motor, or to increase starting speed. Thus, the initial combustion may occur at rest or very low speeds.
However, the inventors herein have recognized several issues with such approaches. First, direct injection fuel system can add significant cost due to higher fuel injection pressure, the unfriendly environment of the combustion chamber for the injector, and requirement for additional packaging space. However, in the above systems, direct injection is utilized to provide fuel to the cylinder before rotation, and thus appears to be a required component.
To address the above issues, a method is provided for controlling an engine during a start, the method comprising: before rotation of the engine: opening an intake valve of at least one cylinder and starting injection of fuel from a port injector coupled to the cylinder so that at least some fuel enters the cylinder; closing the intake valve; and performing a spark in the at least one cylinder.
In this way, it is possible to utilize port injection to provide fuel to a cylinder before engine rotation begins, yet reduce reliance on direct injection.